Heat insulating enclosure



April 8, 1958 www if A. R. BLACKBURN ET Al. I

HEAT INSULATING ENCLOSURE Filed Oct. 8. 1954 2 Sheets-Sheet l INVENTORSATTORNEYS p'i 5, 1958 A. R. BLACKBURN ET AL 2,829,608

HEAT- INSULATING ENcLosuRE Filed Oct. 8. 1954 2 Sheets-Sheet 2 III,

ATTORNEYS United States Patent O HEAT INSULATING ENCLOSURE Andrew R.Blackburn, Westerville, and Richard E. Steele, Worthington, Ohio,assignors to Ram Incorporated, Columbus, Ohio, a corporation of MichiganApplication October 8, 1954, Serial No. 461,082

Claims. (Cl. 109-33) This invention relates generally to a heatinsulating wall structure for an enclosure. More particularly, theinvention is directed to an enclosure wall structure having a layer ofpermeable material interposed between inner and outer walls of theenclosure with means for introducing a fluid into the permeable mass tomaintain moisture therein so that upon exposure to flame or extreme heatthe wall structure will not become unduly heated but will tend todissipate the heat by vaporization of the fluid in the permeable mass.

Numerous previous attempts have been made to devise safes, file cabinetsand other receptacles for containing or storing valuables of all kinds,as well as enclosure wall structures in general which will be resistantto and thereby protect the articles stored against damage by ame orextreme heat. In the majority of these receptacles or enclosures, theprotection afforded the stored articles is secured by thermal insulationexteriorly of the inner storage space which will be effective for apredetermined period of time in preventing excess temperature risewithin the receptacle due to high temperature existing exteriorly of thereceptacle. Thus, the walls of the protective receptacle have been madeof material of low heat conductivity or a thermal insulating materialinterposed between inner and outer walls of the protective container.

These previously designed receptacles or enclosures are effective onlyto the extent that the specially constructed walls thereof preventconduction of heat inwardly to the articles contained therewithin.Although llames may be prevented from reaching the interior space orcompartments, nevertheless suicient heat may be conducted through thewalls of the container so that the objects or materials stored thereinbecome scorched or otherwise damaged by the heat. Generally, the obviousapproach to improve the fire or heat insulating qualities of thecontainer is to increase the thickness of the container walls. Such anincrease in thickness obviously not only increases the weight of thereceptacle, but also reduces the effective storing capacity of thecontainer for any particular set of outside dimensions.

Fire resistant receptacles, such as safes and tiling cabinets, aregenerally rated on an hourly basis as to the period they will beeffective in preventing excessive temperature rise within thereceptacle. In other words, a particular fire resistant receptacle israted as to the period of time which it will restrict heat transfer tothe interior of the receptacle which would raise the temperature withinthe cabinet to the ignition point to cause charring or burning of thearticles contained within the receptacle.

Plaster, having a low heat transfer constant in the order of 0.4 B. t.u.s/sq. ft./hour/ F., has been used in many prior fire resistantstructures. In such structures, plaster has been used not only becauseof its insulating properties but also because it has a characteristic ofabsorbing a substantial amount of heat causing the plaster to break downand dehydrate with the freed water, in turn, absorbing heat as it ischanged into steam. This absorption of heat may run somewhere between800 and 1000 2,829,608 Patented Apr. 8, 1958 fice B. t. u.s/lb. Bymaintaining the plaster in a moist state, exposure of the plaster tohigh temperatures will not result in dehydration and breaking down ofthe plaster. Accordingly, it will retain its heat insulating propertiesand continue to absorb heat as long as the moisture content ismaintained within the plaster.

It is a principal object of this invention to provide a lire or heatinsulating wall structure employing a permeable mass which may beinternally subjected to fluid pressure so that the mass is maintainedina moist condition and thus relatively cool by evaporation of the uidfrom the permeable mass when exposed to high temperature conditions.

It is another object of this invention to provide a fire or heatinsulating receptacle having inner and outer spaced walls and apermeable mass disposed intermediate said walls with passage meansextending through said mass and communicating with a source of fluidpressure through a temperature responsive valve whereby upon exposure toexcessive heat, said temperature responsive valve will admit fluidpressure to said passage to maintain a supply of fluid in said masswhich is evaporated on exposure to heat to retain the receptacle in arelatively cool state.

It is a further object of this invention to provide a re or heatinsulating receptacle having spaced walls with a permeable mass disposedtherebetween, passage means formed in said mass to admit fluid pressurethereto and a fluid supply carried by said receptacle with means topressurize said fluid supply upon the receptacles being exposed toexcess heat whereby iluid will be forced through said passage means andinto said permeable mass to cool said walls of said receptacle.

It will be evident from the description given hereinbelow of thespecific embodiments of the invention illustrated, that the wallstructure of the instant invention iS equally adaptable to and effectivefor use in the construction of stationary storage receptacles such assafes, filing cabinets and storage boxes of all kinds, as well as thewalls of larger enclosures and rooms to produce a structure which willresist the destructive action of high heat or ame.

The above and other objects of the instant invention will becomeapparent from the following description of the specific embodimentsillustrated on the accompanying drawings in which:

Figure 1 is a perspective view with parts thereof in sectionillustrating one application of the instant invention;

Figure 2 is a fragmentary sectional view taken on line 2 2 of Figure l;

Figure 3 is a partial perspective view illustrating the generalformation of the conduit disposed interiorly of the walls of the cabinetof Figure l;

Figure 4 is a partial sectional view of a modified form of heatinsulating receptacle.

Referring specifically to Figure 1 of the drawings, there is shownthereon a safe cabinet 10 constructed with the wall structure thereofembodying the features of the instant invention. The cabinet has a pairof doors 11 and 12 hingedly supported along the sides of the cabinetopening on hinges 13. A suitable latch 14 is provided to retain thedoors in their closed position as desired and a combination lock 15mounted to operate in conjunction with the latch 14 to lock the doors 11and 12 in their closed position. In the illustrated embodiment a base 16is provided to support the cabinet.

As illustrated by the sectionalzed portion of Figure 1, the cabinetdoors 11 and 12 are formed with inner and outer spaced walls 17 and 18with a heat insulating mass 19 disposed intermediate such walls andreinforced by wire mesh 20. On the drawings, the doors `11 and 12 havenot been shown constructed to incorporate the permeable plastic mass anda passage for fluid therein which, as will become apparent from thedescription hereinbelow, is an important feature of the instantinvention. The construction illustrated in Figure 1 for the doors 11 and12 removes the necessity for providing exible connections to conduct thepressurized fluid to the hinged doors. However, it will be readilyappreciated that Within the scope of the instant invention, the doors 11and 12 may be so formed as to incorporate the features of the wallstructure described hereinbelow with regard to the wall structure of therest of cabinet 10.

Figure 2 most clearly illustrates the structural characteristics of thewalls of cabinet 10. This wall structure is formed with an outer wall25, which serves as the exterior wall of the cabinet, and an inner wall26 spaced from the outer wall and defining an interior chamber orcompartment which forms the storage space of the cabinet. The inner wall26 is provided with a plurality of perforations 27 through "'hich vaporsgenerated within the wall structure may flow into the storagecompartment. It will be recognized that the safe is not pressure tightso that such vapor may seep out without there being a pressure build-upwithin the safe.

A mass or layer 28 of permeable material is disposed intermediate theWall 26 and the outer wall 25 and is shown in Figures l and 2 asdisposed in contact with the inner surface of outer wall 25. Preferablythis permeable mass consists of a plaster such as disclosed anddescribed in Patent 2,632,209. Such plaster has characteristics ofpermeability which permit a fluid to be expelled thereinto and therebykeep the plaster in a moist condition. A passage is formed within themass as by a conduit 29 imbedded within such mass and extending back andforth within substantially the entire area of the cabinet wall structurecovered by the layer of permeable material. Conduit 29 is perforated asshown at 30 on Figure 3 to permit fluid such as water to :be forcedoutwardly into the permeable mass 28. Subjecting the passages within thepermeable mass to a pressurized fluid results in maintaining the mass ina moist state to preclude undue temperature rise upon exposure toextreme heat.

Conduit 29 extends outwardly through the outer wall 25 and is providedwith a coupling 31 and a suitable temperature responsive valve 32, whichvalve in turn is connected to a supply pipe 33 leading to a source ofuid under pressure (not shown). The temperature responsive valve 32 maybe of any suitable construction and functions to normally maintain thepressure existent in pipe 33 out of communication with conduit 29.However, such valve is disposed outwardly of the cabinet and thereforeupon being subjected to ame or extreme heat is actuated to connectconduit 29 with the fluid pressure in pipe 33. This valve actuationadmits fluid into the conduit which flows outwardly into the permeablemass 28 to produce the protective moist condition within the mass toresist the destructive action of ame or extreme heat exteriorly of suchcabinet.

Figure 4 illustrates a further embodiment of the instant inventionemploying a layer of permeable material between the spaced inner andouter walls. This embodiment has the additional advantage as comparedwith the embodiment described hereinabove in that it carries, as aself-contained part thereof, a readily available iluid supply and meansfor pressurizing such supply.

The receptacle shown in the fragmentary sectional view of Figure 4, hasan outer wall 40 and an inner wall 41 spaced from said outer wall anddefining an interior compartment for retaining articles to be stored.Intermediate the outer and inner walls 40 and 41 there is provided amass or layer 42 of permeable material disposed in contacting relationwith the outer surface of wall 41 and spaced from the outer wall byangular spacing members 43 secured at spaced positions to the outerwall. The permeable mass 42 has formed therein passages 44 which serveto conduct to the various points within the mass 42 the fluid which isto be expelled into such mass to maintain it in a moist state and thusperform the requisite cooling action. An aperture 45 is provided in theouter wall 40 to permit egress of the vapor from the receptacle whichmay be produced upon exposure of permeable mass 42 to high temperaturecondlitions.

As illustrated in the embodiment of Fig. 4, the receptacle has an opentop and is provided with a cover or door 46 hinged as by hinges 47 tothe side wall structure of the receptacle. Cover 46 is constructed in amanner similarly to the receptacle wall structure hereinabove describedand thus has an outer wall 48, an inner wall 49 and a permeable mass 50formed as a layery intermediate said walls. Such layer is in contactwith the outer surface of the wall 49 and spaced from wall 418 bysuitable angular members 51. A passage 52 is formed within the permeablemass to convey therethrough the fluid which is to be expelled outwardlyinto the mass. Such outer wall is also provided with an aperture 53 topermit vapor to flow out of the cover.

A flexible tube 54 is provided to couple the passage 52 in a door 46with the passage 44 formed in the Wall structure of the receptacle. Theslack in tube 54, as shown in Figure 4, permits opening of the cover ordoor 46 without breaking the communication between passage 52 andpassage 44. As mentioned hereinabove, it will `be readily appreciatedthat the form of construction of door 46 in Figure 4 could be applied inthe construction of doors 11 and 12 of the embodiment illustrated inFigures 1 through 3 so that such doors would be characterized by havinga wall structure as incorporated into the walls of the cabinet 10.

The lower portion of inner wall 41 forms a sump or reservoir whichretains a fluid F to be utilized in cooling the receptacle by its beingexpelled through permeable masses 42 and 50. A tube 61 extends through aseal 62 in the wall 41 to connect the passage 44 while its opposite endextends downwardly into the fluid supply F to a point near the bottom ofthe supply sump.

At a point on the wall 41 above the sump or reservoir 60, angles 65 aresecured as by welding around the interior of wall 41. These anglessupport a plate 66 which separates the iluid reservoir or sump from achamber C which is to serve as the article storing compartment of thereceptacle. Plate 66 is secured to angles 65 by suitable bolts 67 with agasket 68 interposed between the edge of the plate and the angles toseal the reservoir or sump from communication with the compartment C.

In view of the fact that the iluid F carried within the sump orreservoir 60 exists in such reservoir under atmospheric pressure, meansmust be provided to force such fluid outwardly through tube 61 andthence through passages 44 and 52 to be expelled into the permeablemasses or layers 42 and 50. Such a pressurizing means is provided by asealed cartridge 70 mounted within the reservoir on brackets 71 securedto the inner wall 41. Cartridge 70 may contain any suitable pressurizedgas such as, for example, carbon dioxide.

To puncture cartridge 70 and thereby release the pressurized gascontained therein, a temperature responsive puncturing device 72 ismounted on the exterior wall 40. This device has a housing 73 with apuncturing pin 74 having an enlarged head 75 slidably received withinsuch housing and a spring 76 continuously biasing pin 74 toward thecartridge 70. Pin 74 has a sharpened puncturing point 77 and extendsinwardly through apertures provided in the outer and inner walls 40 and41 to be disposed adjacent the cartridge 70. As illustrated, a suitableguide or bearing 78 is disposed adjacent the inner wall 41 within thepermeable mass 42 to slidably support pin 74.

An annular body of material 79 is disposed within housing 73 to surroundthe pin 74 and retain it, against the biasing force of spring 76,outwardly away from contact with cartridge 70. Housing 73 is providedwith an opening 80 adjacent the underside thereof. The material 79 is soselected as to have a melting point temperature approximately equal tothe upper temperature at which it is desired that the receptacle besubjected to the cooling action provided by maintaining the permeablemasses 42 and 50 in a moist state. Upon the temperature responsivedevice 72 being exposed to this temperature, the material 79 melts andflows out of housing 73 through opening 80. Under the urging of spring76, pin 74 with its sharpened point 77 moves inwardly to puncturecartridge 70 and thus release the pressurized gas contained therewithinto subject fluid F to such pressure. In turn, the iiuid F is forced outthrough tube 61 into passages 44 and 52 and thence expelled into thepermeable masses 42 and 50 which has a cooling effect on the wallstructure so that the articles stored within the receptacle or containerare protected from the extreme heat existent exteriorly of thereceptacle.

ln actual applications of the instant invention, the pressure applied inforcing uid into the permeable mass may be in the order of 2() lbs./sq.in. It has been found that this pressure is adequate to keep waterwithin the pores of the permeable mass and thereby keep the mass in amoist condition. In this condition breaking down and actual dehydrationof the plaster will not start, or at least will only occur to a limiteddegree upon exposure of the wall structure to high temperatures. As heatis conducted through the permeable plaster mass tending to raise thetemperature of such mass, the iiuid contained therewithin will beevaporated, absorbing the heat so that the temperature of the wallstructure will not rise above 212 F. Thus the receptacle is maintainedfireproof as the evaporated uid is replaced by fluid forced into thepores of the permeable mass.

Having thus described my invention, what we claim is:

l. A heat insulating receptacle comprising an inner wall defining anarticle storing compartment interiorly thereof, an outer wallsurrounding said inner wall and spaced therefrom to provide a cavityintermediate said walls, a permeable mass disposed in said cavity, saidmass having passage means formed therein, a cover for said receptaclehaving parallel walls and a layer of permeable material positionedintermediate said parallel walls, said layer having a passage therein,means for connecting said passage in said layer with said passage meansin said permeable mass, a pressure tight liquid supply reservoir carriedby said receptacle, tube means terminating within and adjacent thebottom of said reservoir and communicating with said passage means toconduct liquid from said reservoir to said passage means, a cartridgecontaining gas under pressure mounted within said reservoir, andtemperature responsive puncturing means operatively associated with saidcartridge to puncture said cartridge and release the gas pressuretherein upon the occurrence of excessive temperature conditions adjacentsaid receptacle whereby liquid in said reservoir will be forced throughsaid tube means to said passage means and said passage and into saidpermeable mass and permeable material to preclude the occurrence ofexcessive temperature conditions within said receptacle.

2. A heat insulating enclosure wall structure comprising a layer ofpermeable plaster material having a multitude of intercommunicatingpores dispersed therethrough, said layer having a passage larger thansaid pores extending therethrough communicating at a plurality of pointsintermediate its ends with the pores of said material interiorly of saidlayer to conduct liquid directly to the pores within said plastermaterial, means connecting said passage with a liquid supply, and meansresponsive to excessive temperatures adjacent said wall structure tosupply liquid from said liquid supply to said passage andintercommunicating pores in said plaster material so that internaldehydration of said plaster material is substantially precluded and heattransferred to said wall structure effects vaporization of moisture fromthe pores of said plaster material to lprevent undue temperature rise insaid wall structure.

3. In a heat insulating receptacle, a wall structure having an innerwall defining an article retaining compartment and an outer wallsurrounding and spaced from said inner wall, a layer of permeableplaster material disposed intermediate said inner and outer walls andhaving a multitude of intercommunicating pores dispersed therethrough,said layer having a passage larger than said pores extendingtherethrough communicating at a plurality of points intermediate itsends with the pores of said material interiorly of said layer to conductliquid directly to the pores Within said plaster material, meansconnecting said passage with a liquid supply, and means responsive toexcessive temperatures adjacent said wall structure to supply liquidfrom said liquid supply to said passage and intercommunicating pores insaid plaster material so that internal dehydration of said plastermaterial is substantially precluded and heat transferred t0 said wallstructure elfects vaporization of moisture from the pores of saidplaster material to prevent undue temperature rise in said wallstructure.

4. In a heat insulating receptacle, a wall structure having an innerwall defining an article containing compartment and an outer wallsurrounding and spaced from said inner wall, a layer of permeablematerial disposed intermediate said inner and outer walls, said layerhaving a passage therein, means connecting said passage to a pressuretight liquid supply, a cartridge retaining a supply of gas underpressure and mounted to communicate said gas under pressure to saidliquid supply, and temperature responsive means including a cartridgepuncturing element mounted adjacent said cartridge to puncture saidcartridge upon the occurrence of excessive temperature conditions tocommunicate said gas pressure to said liquid supply thereby forcing suchliquid into said passage to maintain said layer of permeable material ina moist condition.

5. A heat insulating receptacle comprising an inner wall defining anarticle storing compartment interiorly thereof, an outer wallsurrounding said inner wall and spaced therefrom to provide a cavityintermediate said walls, a permeable mass disposed in said cavity, saidmass having passage means formed therein, a pressure tight liquid supplyreservoir carried by said receptacle, tube means terminating within andadjacent the bottom of said reservoir and communicating with saidpassage means to conduct liquid from said reservoir to said passagemeans, a cartridge containing gas under pressure mounted within saidreservoir, and temperature responsive puncturing means operativelyassociated with said cartridge to puncture said cartridge and releasethe gas pressure therein upon the occurrence of excessive temperatureconditions adjacent said receptacle whereby liquid in said receptaclewill be forced through said tube means to said passage means and intosaid permeable mass to maintain such mass moist and thereby prevent theoccurrence of excessive temperature conditions within said receptacle.

References Cited in the le of this patent UNITED STATES PATENTS 5,582Fitzgerald May 16, 1848 66,062 Ashcroft June 25, i867 86,356 Bryant Feb.2, 1869 2,520,972 Siple Sept. 5, 1950 FOREIGN PATENTS 5,233 GreatBritain Mar. 4, i907

